Development of a novel bioabsorbable implant that is substituted by adipose tissue in vivo

Abstract

Recently, adipose tissue has been regenerated by combining scaffolds, growth factors, and/or adipose-tissue-derived stromal cells. However, the safety of growth factors and adipose-tissue-derived stromal cells has not been confirmed in cancer patients. We reported the regeneration of adipose tissue in the internal space of a polypropylene mesh containing a collagen sponge (CS), without using any growth factors or cells. We herein explored the formation of adipose tissue, using the bioabsorbable implant containing CS, in rats. We prepared the implants without and with CS, using threads of either poly-l-lactide-co-ε-caprolactone or poly-l-lactic acid (PLLA), and measured their strengths. The procedure was performed in the rat inguinal region. In the control group, no operative procedure was performed. In the sham-operation group, skin incision without implantation was performed. The other groups received CS alone and the 2 implants with and without CS. The areas of formed tissue and adipose tissue inside the implants and the remnants of CS were evaluated. All implants maintained the internal space before implantation. At 6 and 12 months after implantation, the internal space was maintained and the formation of adipose tissue was promoted in the 2 PLLA groups. At 6 months, the internal space was maintained, and more adipose tissue was formed in the PLLA-with-CS group than in the PLLA group. Porcine collagen was absorbed within 3 months. The PLLA implant with CS is a novel bioabsorbable implant that is replaced with autologous adipose tissue after implantation.

Bifunctional scaffolds for the photothermal therapy of breast tumor cells and adipose tissue regeneration

“…22,23 It has been reported that adipose tissue can be regenerated by combining a 3D biodegradable porous scaffold with adiposederived stromal cells or bone-marrow derived mesenchymal stem cells. 24,25 A 3D scaffold for adipose tissue engineering should bear soft tissue-like mechanical properties, biocompatibility and biodegradability. 25 Gelatin has been used for the preparation of tissue regeneration scaffolds because of its high bioactivity, low antigenicity and low immunogenicity.…”

Preliminary Report of De Novo Adipogenesis Using Novel Bioabsorbable Implants and Image Evaluation Using A Porcine Model

“…In phosphate-buffered saline at 37° C,PLLA was degraded to 50% by weight within two years and PGA was completely degraded within two to three months [25]. This implant needs to be lled with the formed adipose tissue inside at least one year [12,13]. Therefore, in the next experiment, we need to investigate the regeneration of adipose tissue over a year after implantation using ultrasonography.…”

“…Mechanical force also affects adipogenesis, and an in vitro study reported that adipogenesis from ASCs is inhibited by mechanical compressive force [21] or mechanical stretch [22]. In our previous in vivo study, we reported the importance of maintaining the internal space for adipogenesis [12,13]. Large volumes of adipose tissue were regenerated via an autologous fat transfer using bioabsorbable, polycaprolactonebased scaffolds in a porcine model [23] and poly-4-hydroxybutyrate mesh scaffolds clinically [24].…”

“…We developed an innovative method of breast reconstruction using a bioabsorbable implant that is substituted by newly-formed adipose tissue after implantation without the use of growth factors or cells [12,13]. This implant aggregate consists of a poly-L-lactic acid (PLLA) mesh implant containing CS.…”

“…The maintenance of the internal space in vivo for approximately one year after implantation is essential for the formation of adipose tissue using this PLLA implant in a rodent model [13]. However, the amounts of formed adipose tissue in rodent and rabbit models were not su cient to ll the volume required for breast augmentation following clinical mastectomy [12,13].…”